麻豆传媒

WASHINGTON -- Uninterrupted anticoagulation during atrial fibrillation ablation was associated with less bleeding when using dabigatran (Pradaxa) than warfarin (Coumadin), the RE-CIRCUIT trial showed.

Major bleeding events during ablation and up to 8 weeks afterward -- the primary endpoint -- occurred at a rate of 1.6% on dabigatran compared with 6.9% on warfarin -- a 77.2% relative risk reduction (five versus 22 patients, P<0.001), , of Johns Hopkins, and colleagues reported here at the American College of Cardiology (ACC) meeting and simultaneously online in the New England Journal of Medicine.

Most events that occurred were in the first 7 days, and dabigatran also cut periprocedural pericardial tamponade and groin hematomas significantly. Minor bleeding events didn't differ between groups. The only thromboembolic event in the trial occurred in the warfarin group.

"It reinforces that periprocedural anticoagulation works, but more importantly it refutes the concerns we had about dabigatran in relation to the fact that it may have bleeding issues," commented , of Massachusetts General Hospital in Boston.

With limited data on non-vitamin K oral anticoagulants (NOACs) in this setting, the researchers noted, most electrophysiologists have interrupted the NOAC and switched to vitamin K antagonists for high-risk patients before the procedure "out of concern that bleeding complications could lead to worse outcomes in the presence of an 'irreversible' anticoagulant."

"However, the practice of switching anticoagulants is cumbersome for patients and physicians, and the growing use of non-vitamin K antagonist oral anticoagulants has made this approach impractical," the researchers noted.

While the trial only looked at one NOAC, there could be a class effect, Calkins told 麻豆传媒 at an AC press conference.

One thing that's "notable about dabigatran is having a reversal agent," he said. "To me, when catastrophe hits, that’s really reassuring to know it's on the shelf."

Although the reversal agent for dabigatran, idarucizumab (Praxbind), became available during the trial, "all the bleeding events in the dabigatran group were managed without the need for dabigatran reversal, which is reassuring," Calkins' group noted.

Singh agreed that the findings likely would generalize to whatever NOAC patients are on, but noted it would be interesting to see head-to-head comparison data among the drugs in the class.

The trial included 704 patients scheduled for catheter ablation of paroxysmal or persistent atrial fibrillation (635 actually got the procedure) who received either dabigatran (150 mg twice daily) or warfarin (target international normalized ratio 2.0 to 3.0) for 4 to 8 weeks uninterrupted before the procedure, during it, and for 8 weeks afterward.

While the researchers acknowledged a limitation in the open-label design, they used blinded adjudicated end-point assessment.

Potential mechanisms for less bleeding with dabigatran may be direct thrombin inhibition rather than effects on coagulation factors, the shorter half-life of dabigatran, and the presence of normal levels of factor VII with it.

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